Investigation of the climate-driven periodicity of shallow groundwater level fluctuations in a Central-Eastern European agricultural region

The distribution and amount of groundwater, a crucial source of Earth’s drinking and irrigation water, is changing due to climate-change effects. Therefore, it is important to understand groundwater behavior in extreme scenarios, e.g. drought. Shallow groundwater (SGW) level fluctuation under natural conditions displays periodic behavior, i.e. seasonal variation. Thus, the study aims to investigate (1) the periodic behavior of the SGW level time series of an agriculturally important and drought-sensitive region in Central-Eastern Europe – the Carpathian Basin, in the north-eastern part of the Great Hungarian Plain, and (2) its relationship to the European atmospheric pressure action centers. Data from 216 SGW wells were studied using wavelet spectrum analysis and wavelet coherence analyses for 1961–2010. Locally, a clear relationship exists between the absence of annual periodic behavior in the SGW level and the periodicity of droughts, as indicated by the self-calibrating Palmer Drought Severity Index and the Aridity Index. During the non-periodic intervals, significant drops in groundwater levels (average 0.5 m) were recorded in 89% of the wells. This result links the meteorological variables to the periodic behavior of SGW, and consequently, drought. On a regional scale, Mediterranean cyclones from the Gulf of Genoa (northwest Italy) were found to be a driving factor in the 8-yr periodic behavior of the SGW wells. The research documents an important link between SGW levels and local/regional climate variables or indices, thereby facilitating the necessary adaptation strategies on national and/or regional scales, as these must take into account the predictions of drought-related climatic conditions.     

Intraplate volcanism in the Danube Basin of NW Hungary: 3D geophysical modelling of the Late Miocene Pásztori volcano

International Journal of Earth Sciences - Three-dimensional geophysical modelling of the early Late Miocene Pásztori volcano (ca. 11–10 Ma) and adjacent area in the Little...     

Giant infrared bubble in Cepheus

A ring-shaped infrared emission region is recognizable on the IRAS Sky Flux images of a Cepheus region which happens to include the association Cepheus OB 2. The ring is easily visible both at 60 and 100 microns. The approximate galactic coordinates of its centre arel=102°.8 andb=+6°.7, with an outer diameter of 7 deg. IC 1396 and several otherHii regions, such as S 129, S 133, S 134, and S 140 are apparently parts of the ring. If it is assumed that these Hii regions are physically connected to the ring its distance must be about 900 pc and its diameter 120 pc. The existence of several arc-shaped H filaments along the ring, the proper motion of the nearby runaway star Cephei, and the possible presence of the [Fex] 6375 interstellar line in the spectra of two stars of Cep OB 2 combine to suggest that the infrared ring might well be a result of a supernova explosion which occurred in this region about 2–3 million years ago.     

Very short baseline interferometry: assessment of the relative stability of the GPS stations at the Yebes Observatory (Spain)

Using a very short baseline interferometer, the relative stability of the YEBE and YEB1 GPS stations at the Yebes Observatory (Spain) is assessed. A baseline length bias of 1 mm was found between estimates from different observed frequencies due most likely to phase center errors resulting from antenna calibration uncertainties and/or phase center migrations caused by the electromagnetic coupling of antenna and monument. Also a bias of 0.5 mm in the vertical component of the baseline length was found between estimates from different cut-off elevation angles due to elevation-dependent errors as phase center and multipath. In addition to these biases, significant variations in the horizontal component of the baseline length were found, mostly in the form of a trend of ?0.45 ± 0.10 mm/yr and an annual oscillation of amplitude 1 ± 0.1 mm and phase 155 ± 5 (beginning of June). The annual oscillation showed a high correlation with ambient temperature variations. Bedrock thermal expansion seems not to be a significant contributor to the annual variation due to the excellent agreement between the phases of the baseline and temperature annual signals. Thermoelastic expansion of the station monuments, which are comprised of concrete pillars and buildings, driven by the sunshine heating, is likely the origin of this oscillation. Near-field multipath and phase center errors are also rejected as being the main contributor to the annual signal. Conversely, near-field multipath and phase center errors may significantly contribute together to the time-correlated noise content of the baseline time series at long periods (flicker noise amplitude of 1.2 ± 0.1 mm). This research provides thus an assessment of the GPS station stability at the Yebes Observatory, which may be extended to the level of station-dependent contamination of geophysical and geodetic studies (e.g., plate tectonics, surface loadings, local ties) when similar station installations on top of buildings are used.     

Free rocking response of a regular stone masonry wall with equivalent block approach: experimental and analytical evaluation

The evaluation of the dynamic behaviour of rocking elements is directly correlated to the energy dissipated because of the impacts at the base interface, which can be represented by means of a coefficient of restitution. This schematization is commonly accepted as representative of the out‐of‐plane response of stone masonry walls. An experimental campaign (in a lab environment) aiming at assessing the value of this coefficient for a sacco granite masonry wall is presented in this work. The rocking motion at a predefined bed joint level was induced in the tested specimens in order to validate a novel test setup designed to assess the coefficient of restitution value by means of a realistic reproduction of the rocking behaviour of a single element, under the hypothesis of an infinitely stiff system above the bed joint level. As the main objective of the work was to assess the rocking behaviour of a masonry wall that looses energy at the impacts at a certain joint level, the flexural behaviour was not desirable and had to be avoided. For this purpose, a test setup based on the equivalent block approach was developed. In the final section of this work, comparisons between experimental and numerical results are presented together with some preliminary conclusions on the appropriate modelling strategy and the values of the coefficient of restitution to be used for the seismic assessment of the out‐of‐plane rocking behaviour of this type of sacco stone masonry walls. Copyright © 2013 John Wiley & Sons, Ltd.     

On the application of combined geoelectric weighted inversion in environmental exploration

Geophysical surveying methods are of great importance in environmental exploration. Inversion-based data processing methods are applied for the determination of geometrical and physical parameters of the target model. The use of this geoelectric inversion method is advantageous in environmental research where highly reliable information with large spatial resolution is required. The 2D combined geoelectric inversion (CGI) method performs more accurate parameter estimation than conventional 1D single inversion methods by efficiently decreasing the number of unknowns of the inverse problem (single means that data sets of individual vertical electric sounding stations are inverted separately). The quality improvement in parameter space is demonstrated by comparing the traditional 1D inversion procedure with a 2D series expansion-based inversion technique. The CGI method was further developed by weighting individual direct current geoelectric data sets automatically in order to improve inversion results. The new algorithm was named combined geoelectric weighted inversion, which extracts the solution by a special weighted least squares technique. It is shown that the new inversion methodology is applicable to resolve near-surface structures such as rapidly varying layer boundaries, laterally inhomogeneous formations and pinch-outs.     

Characterization of acid mine drainage sources in the Iberian Pyrite Belt: base methodology for quantifying affected areas and for environmental management

The present work aims to propose a methodology for quantifying the sources of acid mine drainage (AMD) and to characterize the magnitude of the affected areas in the Iberian Pyrite Belt (SW Spain). Such an approach allows the creation of a support tool for managing land and natural resources valorization, which may be easily applied in similar mining regions. The motivation and usefulness of this work can be realized by focusing on two main emerging strategic issues: (1) water resources management, with the example of Alcolea dam that will receive water from affected areas in the Iberian Pyrite Belt; and (2) mineral resources valorization, especially, regarding copper exploration due to increasing market prices. The used methodology included the following general steps: it started with an inventory of the mines in the Iberian Pyrite Belt, followed by field cartography campaigns and finally the quantification of affected areas and contaminant discharges. The results of the present work serve to confirm and quantify the magnitude of the AMD pollution in the Pyrite Belt. A total affected area of about 4,847 ha was estimated. Taking into account this figure and combining it with the annual average precipitation (650 L/m²) results in an estimation of 31,503,680 m³/year of discharging water affected by the presence of sulphides. In this scenario, a total annual contribution of 260,056 tonnes/year was obtained for sulphates, which means more than 712 tonnes a day. In the case of arsenic, a toxic element, the total annual contribution is more than 20 tonnes, or close to 55 kg/day. Regarding copper, this economically interesting metal translates into total contributions of 10,364 tonnes/year in the generating medium. This gave more than 28 tonnes/day, which today sits at 8,200 dollars/tonne. This result suggests that solutions aimed at recovering this resource should be searched. It may represent a financial return at the same time that it would mean overcome environmental liabilities.